If you use pfsspy in work that results in publication, please cite the Journal of Open Source Software paper at https://doi.org/10.21105/joss.02732. A ready made bibtex entry is
@article{Stansby2020,
doi = {10.21105/joss.02732},
url = {https://doi.org/10.21105/joss.02732},
year = {2020},
publisher = {The Open Journal},
volume = {5},
number = {54},
pages = {2732},
author = {David Stansby and Anthony Yeates and Samuel T. Badman},
title = {pfsspy: A Python package for potential field source surface modelling},
journal = {Journal of Open Source Software}
}